// failed because a an item is not deleted public const int FailObliterateItemNotDeleted = 2401;

You could VaultLib.VaultStatusCode for some error information, or call the API's VaultLib.SoapException. GetSoapExceptionXXX() to get a more easy-to-understand error. This is only if the error is coming from Vault. If it's coming from IIS or other part of the server, then you need to see those error codes.